Apparatus for and method of delivering molten glass



Jap. 5, 1937. G, E HOWARD 2,067,142

APPARATUS FOR AND METHOD OF DELIVERINQ MOLTEN GLASS Filed Oct. 18, 19346 Sheets-Sheet 1 6 Sheets-Sheet 2 eEHawayzZ fz@ @gm a 7';

We@ 5y G. E. HOWARD Filed OCt. 18, 1934 APPARATUS FOR AND METHOD OFDELIVERING MOLfIEN GLASS Jan. 5, 1937.

Jan. 5, 1937. G. E. HOWARD APPARATUS FOR AND METHOD OF DELIVERING MOLTENGLASS Filed Oct. 18, 1934 6 SheetSSheet 5 l@ 560 wtf/e @a @a Wd Jan. 5,1937. G E, HOWARD 2,067,142

APPARATUS FOR AND METHOD OF DELIVERING MOLTEN GLASS Filed Oct. 18, 19346 Sheets-Sheet 4 Jan. 5, 1937,a G. E. HOWARD 2,067,142

APPARATUS FOR AND METHOD OF DELIVERING MOLTEN GLASS Filed oct. 18, 1934e sheets-sheets Jan. 5, 1937. G. E. HOWARD APPARATUS FOR AND METHOD OFDELIVERING -MOLTEN GLASS Filed OCt. 18, 1954 6 Sheets-Sheet 6 atentediJan. 5, E37

Arrn'rns ron manon or nativas Maman Grass George E. Howard, Butler,ford-Empire Gompany,

Pa., assigner to Hartford, Conn., a

corporation ci Delaware Application @ctober it, 193i, Serial No. 748,367

11 Eri This invention relates to improvements in apparatus for andmethods of delivering molten glass from a melting tank or like source ofsupply to the molds of a glassware forming machine.

It is usual in order to deliver molten glass from a melting tank to themolds of a glassware forming machine to provide the tank with asubstantially horizontal extension or forehearth having a glass owchannel closed at its outer end and provided with a glass deliveryoutlet in .its bottom adjacent to its outer end. The outer end portionof this `channel thus constitutes a glass delivery or feed chamber.

In actual practice, ilow of glass from the tank to the tank extension orforehearth is suillcient to maintain the amount of glass in theglass owchannel and feed chamber substantially constant irrespective of changesin the rate of delivery of glass from the delivery outlet. In otherwords, the level of the body of livery outlet of the feed chamber issubmerged will be substantially the same, both when the output of glassfrom the delivery outlet is at a maximum, as when glassware of thelargest size that can be made on the associate forming machine is beingmanufactured, and-when there is no output of glass from the outlet, aswhen the outlet has been closed temporarily. 'Ihe rate of ilow orf glassfrom the tank along the channel to the outlet thus will vary from amaximum rapidity when the output is at a maximum to approximately zerowhen the delivery outlet has been closed. In order to permit the mainmumoutput, when required, without lowering the level of the glass in thefeed chamber, 'it is usual to so construct the tank extension orforehearth and so connect it with the tank that a substantial depth ofglass will` be maintained continuously in the dow channel and feedchamber.

The temperature of the glass in the tankat the intake end of theforehearth channel is substantially constant and, generally speaking, ishigher than that requiredl at the delivery outlet at any time. On theother hand, glass oi a higher temperature at the delivery outlet isrequired i'or small articles of glassware than for .larger articles. Therange of proper temperatures in the glass at the outlet may be as muchas 400' F., depending upon the range of sizes of ware to be made fromglass delivered from that outlet.

Since'the rate oi' travel of glass from the tank along the forehearthchannel to the outlet is relatively rapid when the output at the outletis high, it is clear that in the operation oi a forcglass by which thedehearth such as above referred to, the time available for getting theglass from a higher tank temperature at the intake end of the iiowchannel to a lower proper temperature at the delivery outlet decreasesas the amount of temperature reduction to be effected increases.Therefore, if the tank extension or forehearth is constructed `andequipped with temperature regulating mechanism of such character thatheat will be radiated and otherwise dissipated from the glass passing tothe outlet sumciently to eiect a relatively large reduction oftemperature in a minimum of time, as when the output is high andarticles of glassware of a large size are being marie, it is' obviousthat an increase of time, as when the output is lowered for themanufacture of articles of glassware of a smaller size, will tend tocause a still greater reduction of temperature in the glass by the timeit reaches the outlet. although a less reduction of temperature isrequired.

In an attempt to compensate for this undesirable condition, it is usualin actual practice to increase substantially the heat applied locally tothe glass in the forehearth, asby turning up a. burner or burners, theamount of such increase varying according to the change of glass outputthat has been made. This not only necessitates relatively great fuelconsumption but also tends to increase the diierential between thetemperatures of the upper and lower strata of glass passing toward theoutlet. Thus, if the reduction of output and consequent decrease in therate oi travel of the glass toward the outlet are relatively great, thelower layers of glass in the flow channel bome contaminated by theircontact with the refractory walls of the forehearth channel and maycease to move toward the outlet with the slowly moving upper layers ofAglass. Later, when the output has been increased for the manufacture oflarger articles of glassware, with a consequent increase in the rate ofilow of glass ,in the forehearth channel, portions of the contaminatedglass at ,the bottom 'of the ow channel may be entrained with the morerapidly moving upper layers ci glass and cause defects in and loss oiware made from the glass delivered from the outlet.-

Furthermore, since glass is a relatively poor conductor of heat,a-relati'vely long temperature adjusting and stabilizing period isrequired in the operation of glass delivery apparatus now in general usewhenever any substantial change in temperature at the outlet is to beeected, as when a substantial change is to be made in the size of rawthe ware to be made. During such period, the glass delivered from theoutlet is unsuitable for manufacture into glassware of the particularsize required. Likewise, when the delivery of glass from the outlet hasbeen stopped for any substantial period of time for any reason,resumption of delivery of glass from the outlet at a temperature thatrenders it appropriate for manufacture into glassware of any particularsize can be eeeted only after a'temperature regulating and stabilizingperiod of substantial duration.

Diiculties, such as those above pointed out as being incident to theoperation of glass delivery apparatus now in general use, would likewisebe present to a greater or less degree in the operation of such proposedglass delivering orehearths or tank extensions as diier from those inuse in the character and extent of the operating adjustments providedfor regulably controlling the radiation of heat from the surface of theglass passing toward the outlet without any change in the area of thatsurface and/or for regulably controlling the heat applied to the surfaceof the glass passing toward or above the outlet.

. An object of the present invention is to provide glass deliveringapparatus and a method of delivering molten glass which will makeprovision for changes of output of glass from the delivery outlet andchanges of temperature of the glass at the outlet, as required for thefeeding of glass in charges suitable for manufacture into articles ofglassware of sizes that may differ within a wide range without suchchanges being attended by difficulties such as have been pointed outherein as being incident to the operation of devices now in general use.

A further object of the invention is to provide a glass deliveryapparatus which will aiord facilitiesfor utilizing the temperature ofthe glass entering the delivery apparatus as the main factor -incontrolling the temperature of the glass at the feed outlet for alldiierent required conditions of temperature and output of glass at thefeed outlet.

A further object of the invention is to provide a glass deliveryapparatus having facilities for `varying the effective radiation surfaceof the glass between the source of supply in the tank and the outlet andmoving toward the outlet whenever it is desired to change the output ofglass from the outlet, so that the reduction in temperature of the glasspassing from the tank to the outlet will be decreased when the outputofglass at the outlet has been decreased and increased when the outputhas been increased.

A further object of the invention is to provide a glass deliveringapparatus having facilities for causing movement of a, stream of ,glassof rela` tively large area in cross section and having a relativelylarge heat radiating surface from the tank to the delivery end of theapparatus when the output of glass from the outlet is relatively largeand the temperature of the glass at the outlet is to be relatively lowand for causing a more rapid movement to the delivery end of theapparatus of a streampof glass of less area in cross section and havinga smaller area of heat radiating surface when the output isless and thetemperatureof the delivered glass is to be higher.

A further object of the invention is to provide for circulation of glassfrom the tank to the delivery end of the glass delivering apparatus andback into the tank whenever the required output from the outlet of the.delivery apparatus-is less than the maximum possible inflow from thetank to the delivery apparatus, thereby precluding stagnation of glassin the delivery apparatus during periods of low output or shutdown, andtending to maintain the glass in the delivery apparatus in asatisfactory condition and at a satisfactory temperature at all times.

A further object of the invention is the provision of glass deliveringapparatus having facilities for causing circulatory movement of glassfrom a supply tank to the delivery end portion o such apparatus and backto the tank and for varying'the rate of such movement of glass from thetank to an outlet in said delivery end portion to regulably predeterminethe temperature of the glass at the outlet in accordance with the outputof glass therefrom at any given time.

A still further object of the invention is to provide a glass deliveryapparatus that will function in such manner as to cause and/or takeadvantage of circulatory currents of glass in the supply tank adjacentto the intake end of the delivery apparatus, whereby to promotehomogeneity and assure desirable temperature condition of the glassentering the delivery'apparatus.

A still further object of the invention is to provide a glass deliveryapparatus having improved means for directing flow of glass to theoutlet of such apparatus so as to aid in obtaining desirable homogeneityof the delivered glass.

Other objects and advantages of the invention will hereinafter bepointed out or will become apparent from the description of illustrativepractical embodiments of the invention as shown in the accompanyingdrawings, in which Figure 1 is a longitudinal vertical section throughone form of glass delivery apparatus embodying the invention as appliedto a tank furnace, a fragmentary portion of 'which is shown, the viewbeing substantially along the line I-l of Fig. 3;

Fig. 2 is a horizontal sectional view of the glass delivery structure ofFig. 1 with a portion shown in plan, the view being substantially alongthe line 2 2 of Fig. l, except for the portion shown in plan;

Fig. 3 is a transverse vertical section substantially along the line 3 3of Fig. l;

Fig. 4 is a fragmentary horizontal sectionalH view of a modied form ofstructure at the junc-` ture of the associate tank and glass deliveryapparatus of the general type shown in the preceding views;

Fig. 5 is a section substantially along the line 5-5 of Fig. 4;

Figs. 6 to 10 inclusive are similar fragmentary plan views to illustratediierent modes of use of glass delivery apparatus of the general formshown in the preceding views;

Fig. 11 is a. longitudinal vertical sectional view similar to Fig. 1 butshowing a structural embodiment of the invention in which the forehearthchannel is divided longitudinally into but two branches or divisions,the view being the line II-II of Fig. 12;

Fig. l2 is a horizontal sectional view of the structure shown in Fig.11, the view being substantially along the line l2-i2 of Fig. 1l exceptfor a fragmentary portion that is shown in plan;

Fig.`.13 is a transverse vertical section along accrues paratus shown inFigs. 11 to 13, inclusive, the view being substantially along the lineiii-lli of Fig. 15; and

Fig. 15 is a fragmentary horizontal sectional view along the line |5|5of Fig. 14.

In carrying out the invention, I may provide a forehearth or tankextension structure, generally indicated at A, and suitably connect itwith a tank furnace B, so that glass from the tank furnace tends to flowby gravity and head pressure into the channel of the forehearthstructure.

The bottom and side walls of the forehearth structure A may beconstructed of any suitable known materials and in any suitable knownmanner. The walls of the forehearthY structure may include or beprovided with heat insulating material, and may be supported appurtenantto and/or connected with the tank structure in any suitable known way.

In glass delivery apparatus of the general form shown in Figs. 1 to 10,inclusive, the glass receiving channel of the forehearth structure A isdivided longitudinally from lits intake end nearly to its outer end, asby the longitudinal division walls il and i2 (Figs. 2 and 3), into amiddle branch i3 and a pair of similar side branches M and l5,respectively.

I'he bottom of the middle branch I3 may be higher than the bottom of theside branches Iii and i5 from the intake e'nd thereof nearly to theouter end of the middle branch, as clearly shown in Fig. 1, theremaining or outer end portion of the bottom of the middle branchpreferably being inclined downwardly, as indicated at It in Fig. 1, tothe level X of the bottoms of the side branches.

With this arrangement, the depth of glass in the middle branch is lessthan that in each of the side branches when the surfaces of the streamsof glass in these three branches are at the same level, which maycorrespond with the level of the glass in the supply tank.

Also, with this arrangement, glass entering the middle branch from thesupply tank will be taken from a higher level than the lower layers ofthe glass entering the side branches, and thus may have an averagetemperature slightly higher than that of the glass entering each. of theside branches.

The longitudinally extending division walls and I2 may have their outerend portions formed to diverge slightly, as best seen in Fig. 2. Thespace between the divergent outer end portions of the division walls Iland l2 and extending from the extremities of these division walls to thefront wall of the forehearth structure may be said to constitute theglass delivery or feed chamber of the forehearth structure, and thebottom of this space may be provided with a vertical outlet, such asindicated at il in Figs. l and 2. This outlet preferably is locatedapproximately midway between the extremities of the division walls and 2when the latter are located as shown.

Glass from the branches I6 and l5 may pass around the extremities of thedivision walls l .l andA i2 into this delivery or feed chamber, In

Vorder to direct glass from either of the side branches Ml and I5directly over the outlet, the middle portion of the front wall of theforehearth channel may have a rearwardly projecting curved glasscontacting surface, as indicated at I8 in Fig. 2.

The feeding of glass from the feed or delivery chamber through theoutlet |`l may be regulated `known in the art.

The space above the glass in the forehearth structure may be separatedfrom the space above the glass in the supply tank, as by the use of atransverse refractory plate or slab 2| (Figs. 1 and 3) having dependingspaced portions 22, 23 and 24 reaching to or dipping slightly below thesurfaces of the streams of glass in the respective branches of the glassow channel, as shown in Fig. 2.

The depending portions 22, 23, and 2B of the transverse refractorymember 2| thus may serve to skim the glass entering the branches of theforehearth channel.

A transverse refractory plate or slab 25 (Figs. l and 3) preferably alsois provided at a substantial distance in advance of the transversemember 2| for separating the space above the streams of glass intherespective branches of the channel into a rear transverse division orchamber 2S and a front division or chamber 2l (Fig. 1). The transverserefractory member 25 has depending projections 28, 29, land 3|),respectively, (Fig. 2) which may reach to or dip slightly below thesurfaces of the streams of glass in the respective branches of the glassconducting channel of the forehearth.

The chamber 26 has a cover wall provided with suitable openings abovethe lateral branches |63 and 5 of the forehearth channel to accommodatesubstantially vertical refractory impellers 3 I, which may be paddles orsweeps adapted to be oscillated with generally fore-and-aft movements.

The impellers 3l may have upper end portions supported by removablechucks or sleeves 32 which in turn may have head portions removablysecured by clamping devices 33 in vertical slots in oscillatoryhorizontal arms 33.

The arms 33 are supported on vertical rods 35 which may constituteextensions of the rods of pistons 36 in vertical cylinders 31. When thepiston 36 in each cylinder 3l is raised, as by the pressure of airadmitted to its lower end portion, theimpeller 3| with which that pistonis connected will be raised until its lower edge is but very slightlyimmersed in the stream of glass in the underlying branch of theforehearth channel, as to the position shown for the left hand impeller3| in Fig. 3. When each piston 36 is at the lower end of its stroke inits cylinder, as in the position shown for the right hand piston 36 inFig. 3, the impeller 3| with which that piston is connected will belowered until it depends to a substantial distance below the surface ofthe glass in the underlying branch of the forehearth channel, as to theposition shown for the right hand impeller 3| in Fig. 3.

The depth of dip of each impeller into the underlying stream of glassmay be regulated within limits, as by an adjustable stop at the lowerend of the operating cylinder, such a stop being shown in the lowerright hand corner of Fig. 3 as a screw threaded sleeve 38, and beingadjustable vertically by a hand wheel 39.

The reciprocation of each of the impellers vertically to raise and lowerit in the underlying glass stream may be effected by periodicallyadmitting air under pressure to each of the oppo. site ends of theoperating cylinder, as through pipes such as indicated at @il and di forthe right hand cylinder 3l in Fig. 3.

It of course will be understood that the pressure uid will be permittedto exhaust from each end of the cylinder 36 when pressure is beingadmitted to the opposite end thereof. The control of the application andexhaust of. 'uid under pressure to and from the respective ends of eachof the cylinders 3l may be obtained by the use of any suitable timingmechanism, such as the wellknown Hartford I. S. timer.

lThe rack bars le may constitute extensions of the rods of pistons, suchas that which is shown in dotted lines at 5 in Fig. 2, such pistonsbeing reciprocable in horizontal cylinders d5. VThe reciprocation of thepistons d5 in the cylinders it may be effected by admitting andexhausting iiuid under pressure to and from the opposite ends of thecylinders under the control of the timer by'which the operations of thepistons 36 in the vertical cylinders 31 are controlled.

With the construction described, it is obvious that in order to impelglass forwardly in the side periods of dip of the impellers into theVglass of branches of the forehearth channel, it only is necessary totime the forward oscillatory movements of the impellers so as tocoincide with the the underlying streams and to time the return vorrearward strokes of the impellers to coincide with the periods of liftof. the impellers. To reverse the direction in which glass will beimpelled by the action of the impellers 3|, the periods of rearwardoscillatory movements of the impellers are timed tocoincide with theperiods of dip of such impellers into the glass.

Of course, provision may be made by the use of a timer such as describedso that each olf the respective impellers will be controlledindependently of the other impeller, so that one impeller may beemployed to impel glass forwardly in one of the side branches of theforehearth channel while the other impeller is employed to impel glassrearwardly in the other side branch of the forehearth channel, and viceversa.

The depending projections 28, 29, and 30 of the intermediate transverserefractory member 25 serve to damp or-break up any waves or surges thatmight otherwise be transmitted to the glass in the'delivery or feedchamber of the forehearth by reason of the intermittent glass impellingoperations of the impellers 3l.

Means may be provided for applying the glass. in the delivery or feedchamber and while passing thereto in the chamber 21o! the forehearthstructure. To this end, the front wall of the forehearth structure thusmay be provided with openings, such as indicated at 41 (Fig.

.2) adapted to accommodate burners by which a combustible fuel mixturemay be projected into the space above the glass at the juncture of eachof the side branches of the forehearth channel with the delivery orfeedchamber at the outer endof the middle branch.

When the burners 48 are employed, provision may be made for ventingthewaste products of heat to] point.

accedas combustion and' gases from the space above the glass intheforward chamber 2l of the forehearth structure. For this purpose, a.portion of the top wall of the chamber 2l may be so constructed as toprovide outlet chambers s@ (Fig. 3), each having a top including aremovable block lec. `When the blocks 39a are removed, the openings leftconstitute vents or chimneys for products of combustion and waste gasesfrom the burners de.

The structure that has been described may be operated in dierent ways inaccordance with the invention in order to meet different servicerequirements. Some of the ways in whichl such structure may be operatedare illustrated in Figs. 6 to l0 inclusive.

Fig. 6 shows a mode of operation which may be followed when the outputof glass at the outlet il is at a maximum, as when charges of glass ofthe largest size obtainable are required for the manufacture of articlesof glassware of the largest size to be made by the use of the associateforming machine. `When this condition exists, the impellers 3i may bemaintained inactive .at the upper ends of their vertical strokes, andglass from the supply tank may enter all three of the .branches of therespective channels and iiow along these branches, as indicated by thearrows in Fig. 6, to the delivery or feed chamber at the outer ends ofsuch branches. The burners may or may not be employed at this time,depending on whether or not their use is required to preventinequalities of temperature in the dierent streams of glass passing tothe feed chamberv from the 'respective branches of the forehearthchannel. v

Instead of the impellers being retained inactive during this mode ofoperation and the pull through the glass in the feed chamber beingrelied on to. control the rate of movement of the streams of glass alongthe respective channels to'the feed chamber, one or both of theimpellers may be operated at the required speed and to impel glass inthe direction required to aid or oppose the pull at the outlet as aneffective means for controlling the rate of ow and the temperature ofthe glass passing to the feed chamber. 1f desired, an impeller or anadjustable ow regulating gate may be provided for the middle branch ofthe forehearth channel.

In the mode of operation just described, as well as in other modes ofoperation of apparatus embodying the invention, the area of heatvradiating surface of the glass passing to the outlet and the rate oftravel of such glass are selected in view of the temperature of theglass at the intake end of the forehearth channel and the temperaturethat .is desired for the glass at the outlet, so that the reduction oftemperature of the glass during its travel to the outlet will be justsuicient to provide the desired temperature at that Heat from theburners, if used at all, may be primarily for stabilization oftemperature of the glass in the feed chamber or to' promote uniformityof temperature throughout all the glass in the feed chamber.

In the mode of operation illustrated in Fig. 7, the glass' to be fedfromthe outlet is flowing from the tank along the middle channel to thedelivery or feed chamber and excess glass is being returned to the tankalong the side branches of the forehearth channel, all as indicated bythe arrows. For this purpose, the impellers may be operated so as toimpel glass rearwardly in the vside Dfi branches of the -forehearthchannel ata rate ademas which may be adjusted to meet particularrequirements at any given time.

It will be observed that the middle branch of the forehearth channel notonly may be relatively shallow, as shown, but it is protected againstheat loss at its sides by the side branches of the glass conductingchannel of the forehearth. The reduction of temperature of the glasssupplied to the feed chamber by way of the middle channel therefore maybe relatively slight and this mode of operation therefore is welladapted for the feeding of glass at a relatively high temperature and inrelatively small charges appropriate for manufacture into small articlesof glassware.

This mode of operation talso may be used to advantage during shut-downperiods, as conditions within the forehearth thus may be maintainedappropriate to permit prompt resumption of glass feeding operations whendesired.

For the manufacture of articles of glassware of a range of sizes betweenthe large sizes referred to in the description of the mode of operationillustrated in Fig. 6 and the small sizes referred to n. the descriptionof the mode of operation illustrated in Fig. 7, the glass to be 'fed maybe conducted to the delivery or feed chamber by way of the side branchesof the forehearth channel, excess glass being returned to the tankthrough the middle channel, as indicated by the arrows in Fig. 8. lnthis mode of operation, the impellers 3i may be operated to impel glassforwardly in the side branches of the forehearth channel at a rate whichmay be predetermined to meet existing conditions at any given time.

p Figs. 9 and 10 illustrate similar modes oi operation which may beemployed to meet particular service conditions.

As shown in Fig. 9, glass is being supplied to the delivery or feedchamber from the middle branch and through one of the side branches andis being returned to the tank by the second side branch of theforehearth channel. This mode oi operation may be eiected by causing theimpeller for the rst side branch to impel glass forwardly, while theimpeller for the second side branch may be The mode of operationillustrated in Fig. l0 is just the reverse of that shown in Fig. 9.Glass is being conducted to the .delivery or feed chamber through themiddle branch and the second side branch ofA the forehearth channel andis being returned to the tank through the iirst side branch.

In the construction shown in Figs. l to 3 inclusive, the respectivebranches of the forehearth channel are open at their inner ends so thatglass may iiow horizontally thereinto from the supply body in the tank,although the bottom of the middle branch is located at a somewhat higherlevel than the bottoms of the side branches.

In the modied form of construction shown in Figs. 4 and 5, the sidebranches oi the forehearth channel, designated lila and ia,respectively, are closed at their inner ends, as by transverse end wallsindicated at 5d. The middle branch 93a of the forehearth channel may beleft open at its inner end, as in the preceding form of construction.The side branches ida and a of the forehearth channel communicate withthe interior oi' the tank below the glass level in the latter by meansof ports 5l in the bottoms of their inner end portions. I

Thus, when glass is being supplied to the delivery chamber through themiddle branch and is being returned to the tank through the sidebranches, the glass being returned will be delivered back to the tankIat points farther below the surface of the supply body of glass thanwhen the structure shown in Figs. 1 to 3, inclusive is employed. Thiswill eir'ect an improved homogenizing action in the glass at the intakeend of the forehearth, currents being set up therein substantially asindicated by the arrows in Fig. 5.

In apparatus of the general form shown in Figs. ll to l5, inclusive, thechannel of the forehearth structure A is divided longitudinally from itsintake end nearly to its outer end by a single longitudinal divisionwall it@ which may be l0- cated midway of the side walls of the channel,thus providing a pair of similar juxtaposed channel branches ordivisions mi and ft2, respectively.

The portion of the forehearth channel at the outer ends of the branchesibi and 32 and in front of the outer end of the division wall it@constitutes the glass delivery or feed chamber of the forehearthstructure. A vertical outlet it may be provided in the bottom of thisdelivery or feed chamber. The feeding of glass from the feed or deliverychamber may be regu lated and controlled by suitable means, as bymechanism including a reciprocable vertical plunger i@ and a surroundingsleeve 29, as hereinbefore has been pointed out.

Preferably the outer end portion of the division wall it@ is enlarged'gradually and symmetrically in thickness toward its outer end, asindicated at Miha, Fig. l2, the extreme outer end portion of rthedivision wall being suriciently wide and so formed as to provide a pairof similar guard wings or baos it-aa: at approximately opposite sides ofthe outlet its when the latter is 1ocated partially beneath asubstantially semicylindrical open-topped recess or chamber itil-ac inthe outer end of the division wall ith. The outlet tilt preferably islocated nearer to the re-entrant concavely curve'd front face of thedivision wall than to the out/er end or front wall oi the forehearthchannel. Relatively hot glass at .the inner side of either the branchlill or the branch M32 thus cannot pass directly to the outlet butinstead will be guided laterally by the outwardly turned adjacent sideface of the portion of the division wall as such glass passes into theglass delivery chamber at the outer end of the forehearth channel.Consequently, glass from either of the channel branches mi or m2 will bemixed and homogenized in passing around the adjacent guard wing or baiietilt-aa: toward the outlet itil.

The space above the glass in the forehearth channel may be separatedfrom the space above Athe glass in the supply tank by a transverserefractory plate or slab H29, Fig. ll, having depending spaced portions522 and i23, Fig. 12, reaching to or dipping slightly below the surfacesof the streams of glass in the channel branches lui kand m2, as shownfor the part H23 in Fig. ll.

A transverse'refractory plate or slab 525, Fig. ll, has spaced dependingportions H28 and |23, Fig. l2, depending to the surface of the streamsof glass in the channel branches, as shown for the vided with suitableopenings above the ches mi and |02 of the forehearth channel toaccommodate substantially vertical refractory impellers. Such impellersand their operating and 5 supporting mechanisms may be substantially thesame as those which have hereinbefore been described as applicable tothe form of apparatus Ashown in Figs. 1 to 3, inclusive. The samereference characters designate the same or like parts throughout theseveral views of the drawings and it therefore is believed to beunnecessary to repeat. the description thereof. It Enza-f be noted,however, that 1 may provide an impeller Si in contact with the glass inbut one of the two branches of the forehearth cel, as, for example, forthe glass in the brch mi as shown in Figs. 11, 12, and 13.

Apparatus of the particular form shown in Figs. 11, l2, and 13 hasstructural features which are substantially the same as correspondingfeatures of the form `of apparatus shown in Figs. 1 to 3 inclusive. Thesame reference ccters indicate the substantial identity of geny cor-.responding parts ofthe two forms of apparatus.

The operation of the apparatus oi" the twodivisional channel form o fconstruction may be varied at different times to meet dierent serviceconditions. When only one of the branches or divisions of the-forehearthchannel is provided with an impeller si, as shown in Figs. 12 and 13,

and the articles of glassware to be produced from Y charges of glass fedthrough the outlet are within arange of relatively small sizes, theimpeller di may be actuated to cause circulation of glass from the tankalong the branch mi of the fore# hearth6 channel to the delivery end orVfeed chamber portionof that channel and thence back to the tank by wayof the division IM of the channel. Theloss of heat fromv the glass as ita 40 from the tank to the outlet may be controlled within a considerablerange when glass is circlilated in this manner by regulable controlofthe.

connected with the supply tank so as to take ad' vantage of circulatorycurrents of glass in the suppl tank. For example, it is within the pur-`-view fthe invention that the supply tank shall be equipped withsuitable means, such as dis-` closed in -my Patent 1,919,668, grantedJuly 4, 1933, for causing transverse currents of glass at the deliveryend of the supply tank, such for example as those indicated by thearrows 30 in Fig. 12. AThe forehearth structure may be asso- 65, ciatedwith the delivery end of this tankso that the transverse currents ofglass in the tank move past the intake end of the delivery `branch ordivision of the forehearth channel before pass-4 ing thereturn branch ordivision of such fore- 70 hearth channel. Thus, glass that has beencirculated in the tank will enter the delivery branch of the forehearthchannel, as indicated by the arrows |3I' in Fig. 12. The return streamof glass in the other branch or division of theforehearth .channelwillreturn to the supply tank as indione of the branches.

` amaa cated by the arrows m2, Fig. 12, and thus will be entrained withthe transverse currents |30 in the tank so that-the glass that hascirculated through th forehearth channel will be caused t0 7 circulatein and become commingled with the glass of the supply tank before suchglass can again enter the delivery branch or division of the forehearthchannel. This makes for uniformity of temperature and condition of theglass entering the forehearth channel.

Should the supply tank not be provided with any positive means forcausing a transverse circulation of glass therein, then the longitudinalmedian division wall i@ of the two-divisional channel form of forehearthmay be extended, as indicated at E33 in Figs. 14 and 15, to project intothe glass of the supply 'tank a distance suiciently far to assure thatthe glass leaving'the forehearth channel by way -of the returnl 'branchthereof will be diverted into the body of the glass in the `supply tank,as indicated by the arrows i3d in Fig. l5, before being permitted topass into l the delivery branch of the forehearth channel, as

with the currents of glass indicated by the arrows !35 in Fig. l5. Whena range of larger sizes of glassware is to be manufactured, the impellermay be maintained inactive and in its raised position and both branchesof the forehearth channel may be-used as delivery branches so that glassfrom the supply tank will pass along both branches to the delivery endportion or feed chamber. at the outer end of the forehearth channel.`With this arrangement, the loss of heat from the glass passing l'fromthe supply tank to the outlet will be greater than when glass is passingthereto by way of only Such loss of heat also may begreater because ofthe lessening of, the rate of ow movement of Aglass during its travelfrom the supply tank to the outlet. The charges fory the larger articlesoi glassware thus may be fed at a lower temperatlre than the charges forthe smaller articles o f glassware, and such regulation and control oftemperature may be effected without involving substantial changes in anymeans with whichthe forehearth maybe equippedfor applying heat to ltheglass therein. In other words, the heat from the burners may be only`such as to stabilize conditions within the forevhearth and the vcontrolof temperature may be eected by regulable control of the rate of ow ofglass from the supply tank to the outlet and of the area of heatradiating surface of the glass passing to the outlet.

fed from the outlet for the production of charges appropriate formanufacture \into articles of glassware of any size within a wide rangeand therate of Ioutput and the temperature of the glass being fed may bechangedto meet changed service conditions without encountering thediiilicul-v 1. The method of delivering molten glass from a melting tankor like source of supply. compris- By use of the invention, glass of thetempera- .55 ture required and in the volume required may be acca-14aand altering the heat radiating surface of the glass passing to the feedchamber in accordance with a change to be effected in the output ofglass from said outlet.

2. The method of delivering molten glass from a melting tank or likesource of supply,- comprising flowing glass in a stream along a owchannel of'a forehearth from the source of supply to a feed chamberhaving an outlet adapted to be submerged by the glass therein, andaltering the heat radiating surface of the glass stream passing to thefeed chamber and the rate of travel of the glass of such stream inaccordance with a change in the output of glass from said outlet.

3. The method of delivering molten glass from a melting tank or likesource of supply, comprising flowing glass from the source of supply ina stream to a feed chamber having a bottom discharge outlet, maintainingsaid stream at a given width when the glass discharging from the outletis being separated into charges appropriate for4 the manufacture ofarticles of glassware of a given range of sizes, and altering the widthof said stream of glass to increase the heat radiating surface of saidstream whenthe glass discharging from the outlet is to be separated intocharges appropriate for manufacture into articles of glassware of arange of larger sizes and to decrease the heat radiating surface of saidstream when the glass discharging from the outlet is to be separatedinto charges appropriate for manufacture into articles of glassware ofrange of smaller sizes.

4. The method of delivering molten glass from a melting tank or likesource of supply to a feed chamber having a discharge outlet adapted tobe submerged by the glass therein, which comprises flowing glass fromthe source of supply to the feed chamber in a stream of relatively greatwidth when the temperature of the glass discharging from the outlet isto be relatively low and owing glass from the source of supply to thefeed chamber in a stream of less width when the temperature of the glassdischarging from the outlet is to be higher.

5. The method of delivering molten glass from a melting tank or likesource of supply which comprises, providing a feed chamber having abottom discharge outlet at a place adjacent to said source of supply,and owing glass from the source of supply to said feed chamber in astream of a width that is selected according to the reduction oftemperature to be eected in glass passing from said source of supply tosaid feed chamber during any given period of time and is changed whenthe amount of said reduction of temperature is to`be changed.

6. The method of delivering molten glass from a melting tank or likesource of supply which comprises, providing a feed chamber having abottom discharge outlet at a place adjacent to said source of' supply,and iiowing glass from the source of supply to said feed chamber in astream having a heat radiating surface that mined with relation to thetemperature desired for the glass at the outlet at any particular time,and altering the heat radiating surface of the stream of glass flowingto the feed chamber when a different temperature is desired for theglass at said outlet.

7. The method of delivering molten glass from a melting tank or likesource of supply which comhas been predeter` prises, providing a feedchamber having a bottom discharge outlet and a glass flow channel havinga plurality of juxtaposed branches all communicating at their outer endswith the feed chamber and communicating at their inner ends with thevinterior of the tank below'the level of the glass in the latter,predetermining the direction of oW of glass between the tank and thefeed chamber in said respective branches to predetermine the temperatureof the glass at the outlet at any given time, and altering the ow in atleast one of said branches to effect a change in th temperature of theglass at the outlet.

L8. Glass delivery apparatus comprising a forehearth having a channelcommunicating at its inner end with the interior of a melting tank andprovided at its outer end with a glass feed chamber having a dischargeoutlet in its bottom, means dividing the channel of the forehearth toprovide two longitudinally extending branches having separate places ofcommunication at their inner ends with a supply body of glass in thetank and both communicating at their outer ends with said feed chamber,and baffles at the junctures of said branches and said feed chamber,anking said outlet and in spaced relation therewith for causing a streamof glass from either of said branches to enter said feed champrovided atits outer end with a glass feed chamber having a discharge outlet in itsbottom, means l dividing the flow channel of the forehearth to providetwo longitudinally extending branches having separate places ofcommunication at their inner ends with a supply body of glass in thetank and both communicating at their outer ends with said feed chamber,means for causing circulation of glass from the tank through one of thebranches of said forehearth channel to the feed chamberand return ofglass from the feed chamber along the other of said branches to thetank, and means at the juncture of said branches of the forehearthchannel and the tank for causing the return glass from the forehearthchannel to be circulated in the supply body of glass in the tank beforebeing permitted to enter a branch of the forehearth channel. i

10. Glass delivery apparatus, comprising a forehearth having a channelcommunicating at its inner end with the interior of a melting tank andprovided at .its outer end with a glass feed chamber having a dischargeoutlet in its bot-v tom, .means dividing the flow channel of theforehearth into a pair of longitudinally extending branches havingseparate places of communication at their inner ends with the supply ofglass in the tank and both communicating at their outer ends with saidfeed chamber, said forehearth channel communicating with said tank sothat transverse currents in the supply body of glass in the tank passacross the inner end of one of said branches of the forehearth beforepassing the inner end of the second-of said iorehearth branches, andmeans. for causing circulatory movement of glass through said firstbranch of the forehearth channel to the delivery chamber and thence backto the tank through the second branch of said forehearth channel.

ll. Glass delivery apparatus, comprising a forehearth having a channelcommunicating at its inner end with the interior of a melting tank belowthe level of the glass in the latter and provided at its outer end witha glass delivery chamber, a longitudinal wall dividing the ow chan-l lber and thence back to the tank through the accanita second branch ofsaid forehearth channel, and an extension of said longitudinaldivisionwall -of the forehearth channel at the inner end thereof, said extensionprojecting into the supply body of glass in the tank a; distancesufficient to divert the returned glass from the forehearth channel intosuch supply body of glass before permitting any portion of said returnedglass t'o enter a branch of the forehearth channel.

GEORGE E. HOWARD.

